Dynamic electromyographic evaluation of adolescents with traumatic cervical injury after biceps to triceps transfer: the role of phasic contraction.
OBJECTIVE
To characterize the EMG firing pattern of the biceps after transfer to the triceps.


METHODS
Seven subjects (12 arms), 18.0 +/- 1.7 years old, consented to fine wire EMG assessment of the biceps, averaging 23.0 +/- 10.0 months (range: 9 to 45 months) after transfer. Subjects were tested under 3 conditions: (1) single flexion and extension, (2) self-selected alternating elbow flexion and extension, and (3) isometric flexion and extension. A strain gauge electrogoniometer measured elbow movement. Using root-mean-squared values of biceps EMG, ratios of extension/flexion activity were calculated for each muscle. Conventional manual muscle testing grades were obtained before and after surgery.


RESULTS
Median manual muscle testing for elbow extension was 0 before surgery and 4- (range: 3- to 4) following surgery. For each of the 3 conditions tested, the biceps reversed its action to an elbow extensor (p < .05).


CONCLUSIONS
Our findings show that the biceps, after transfer to the triceps in patients with C5 or C6 spinal cord injury, can be trained to activate preferentially during elbow extension, a reversal of its ordinary action as an elbow flexor.
Hutchinson
David
D
Shriners Hospital for Children, Philadelphia, PA 19140, USA. Hutchinson@shrinenet.org
Kozin
Scott H
SH
Mayer
Nathaniel
N
Mulcahey
M J
MJ
Duffy
Theresa
T
Gaughan
John P
JP
D000293:Adolescent; D002574:Cervical Vertebrae; D002648:Child; D004551:Elbow Joint; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D018908:Muscle Weakness / Q000175:diagnosis; D018482:Muscle, Skeletal / Q000637:transplantation*; D019637:Orthopedic Procedures / Q000379:methods; D011182:Postoperative Care / Q000379:methods; D011782:Quadriplegia; D016059:Range of Motion, Articular / Q000502:physiology; D012680:Sensitivity and Specificity; D013119:Spinal Cord Injuries / Q000175:diagnosis / Q000601:surgery*; D034941:Upper Extremity; D055815:Young Adult